An internal combustion engine includes an engine block, a piston, a cylinder head, and a valve train. The engine block includes a cylinder block including a cylinder bore and a crankcase defining a crankcase chamber with a crankshaft positioned within the crankcase chamber. The piston is coupled to the crankshaft and configured to reciprocate within the cylinder bore. The cylinder head is coupled to the cylinder block. The valve train includes a camshaft, a first and second pushrod, a first and second rocker arm, an exhaust valve housed, and an intake valve. The first rocker arm, the second rocker arm, the exhaust valve, and the intake valve each include at least a layer of a low friction material. The first and second pushrod each pass through a pushrod seal to prevent fluid from reaching the rocker chamber to fluidly isolate the rocker chamber from the crankcase chamber.

Provided are a stationary mold configured to form a portion of a bearing portion of a crankshaft and a portion of a crankcase, and a movable mold including a plurality of bore pins respectively defining cylinder bores of cylinders. The bore pins are arranged to correspond to a cylinder bank including the plurality of cylinders. The movable mold is matched with the stationary mold such that portions of outermost ones of the plurality of bore pins in a series direction are each inclined away from another one of the plurality of bore pins adjacent to the outermost bore pin in the series direction toward a distal end of the outermost bore pin, where the series direction represents a direction in which the plurality of bore pins are arranged.

A liner for a cylinder of an internal combustion engine can comprise a hollow cylindrical wall or body having an inner surface, an outer surface opposite the inner surface, and open top and bottom ends. The outer surface can be without any sealing grooves in at least a bottom portion thereof. A relatively thin portion of the wall or body can be provided below a thick portion of the wall or body, and may reach the bottom end of the wall or body. An angled transition can define a change in thickness from the thick portion to the thin portion.

A linerless engine block includes a polymer matrix composite having an internal surface that defines a bore. The polymer matrix composite has a first thermal conductivity at the internal surface of at least 5 W/m.Math.° C. The linerless engine block also includes a first bond coating disposed on the internal surface within the bore, and a second wear-resistant coating disposed on the first bond coating within the bore such that the second wear-resistant coating is adhered to the polymer matrix composite by the first bond coating. A method of forming the linerless engine block is also described.

A sliding mechanism of the present invention includes a cylinder bore having a thermally sprayed iron-based coating and includes a piston with a piston ring covered with a hard coating composed mainly of carbon.

The thermally sprayed coating has diamond abrasive grains.

An area ratio of the diamond abrasive grains to a surface of the thermally sprayed coating is 0.3 to 1.8%, which enables suppressing wear of the piston ring having the hard coating composed mainly of carbon.

An engine block (10) includes a cylinder liner (120) and a resin block (200). The cylinder liner (120) has a metal outer circumferential surface (122). The resin block (200) includes a first portion (210) and a gap (230). The first portion (210) covers the metal outer circumferential surface (122) of the cylinder liner (120). The gap (230) is positioned outside the first portion (210) and defines a water jacket (232).

A cylinder block includes a body part where a cylinder is formed, an outer wall part made of fiber reinforced resin and surrounding an outer circumference of the body part, and a metal member attached to the outer wall part. The outer wall part is comprised of an inner layer surrounding the outer circumference of the body part, and an outer layer surrounding an outer circumference of the inner layer. A density of reinforcing fiber contained in the outer layer is higher than a density of reinforcing fiber contained in the inner layer. The metal member is attached to the outer wall part so as to contact the outer layer. The reinforcing fiber contained in the outer layer has an electric insulating property.

A cylinder block includes a body part where a cylinder is formed, an outer wall part made of fiber reinforced resin and surrounding an outer circumference of the body part, and a metal member attached to the outer wall part. The outer wall part is comprised of an inner layer surrounding the outer circumference of the body part, and an outer layer surrounding an outer circumference of the inner layer. A density of reinforcing fiber contained in the outer layer is higher than a density of reinforcing fiber contained in the inner layer. The metal member is attached to the outer wall part so as to contact the outer layer. The reinforcing fiber contained in the outer layer has an electric insulating property.

A cylinder block includes a metal body part having a cylinder, and an outer wall part made of fiber reinforced resin, surrounding an outer circumference of the body part. A part of the outer wall part at BDC side in a cylinder axis direction contacts a bottom wall forming part. The outer wall part is comprised of an inner layer surrounding the outer circumference of the body part, and an outer layer surrounding an outer circumference of the inner layer. A density of reinforcing fiber contained in the outer layer is higher than that in the inner layer. A thickness of a part of the inner layer at BDC side in the cylinder axis direction is greater than that of the TDC-side inner layer. A thickness of a part of the outer layer at TDC side in the cylinder axis direction is greater than that of the BDC-side outer layer.

A structural frame is provided. The structural frame includes a bottom surface, first and second cylinder block sidewall engaging surfaces, the first and second cylinder block sidewall engaging surfaces positioned above the bottom surface at a height that is above a centerline of a crankshaft support included in a cylinder block when the structural frame is coupled to the cylinder block.